The multidisciplinary treatment combining IP-containing chemotherapy and surgery was found to be safe and effective for gastric cancer patients with peritoneal metastasis. A phase I study combining i.p. paclitaxel with oxaliplatin and S-1, found no dose limiting toxicity in all dose levels. Grade 3 neutropenia was observed in one patient at recommended phase 2 dose (RP2D) of i.p. paclitaxel of 40 mg/m2. In addition, grade 2 non-hematological toxicities observed were anorexia (n=6/12), fatigue (n=4/12) and nausea (n=2/12).